/************************************************************************
 * Copyright (c) 1990, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 ************************************************************************/



#include "errno.h"
#include "stdio.h"
#include "stdlib.h"
#include "local.h"

/*
 * Various output routines call wsetup to be sure it is safe to write,
 * because either _flags does not include __SWR, or _buf is NULL.
 * _wsetup returns 0 if OK to write; otherwise, it returns EOF and sets errno.
 */
int
__swsetup(FILE *fp)
{
    /* make sure stdio is set up */
    if (!__sdidinit_flag)
        __sinit();

    /*
     * If we are not writing, we had better be reading and writing.
     */
    if ((fp->_flags & __SWR) == 0) {
        if ((fp->_flags & __SRW) == 0) {
            errno = EBADF;
            return (EOF);
        }
        if (fp->_flags & __SRD) {
            /* clobber any ungetc data */
            if (HASUB(fp))
                FREEUB(fp);
            fp->_flags &= ~(__SRD|__SEOF);
            fp->_r = 0;
            fp->_p = fp->_bf._base;
        }
        fp->_flags |= __SWR;
    }

    /*
     * Make a buffer if necessary, then set _w.
     */
    if (fp->_bf._base == NULL)
        __smakebuf(fp);
    if (fp->_flags & __SLBF) {
        /*
         * It is line buffered, so make _lbfsize be -_bufsize
         * for the putc() macro.  We will change _lbfsize back
         * to 0 whenever we turn off __SWR.
         */
        fp->_w = 0;
        fp->_lbfsize = -fp->_bf._size;
    } else
        fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
    return (0);
}
